No idea about chrome issue, I don’t use it.

As to your other questions:
Many firewalls these days include HIPS (host intrusion protection). I think OnlineArmor has HIPS. Do some reading. Make sure it will not conflict with Avast’s behavior shield. Both shouldn’t run at the same time IMO. But only users of OA or Avast experts can confirm if what I say is right.
By conflict I mean either computer troubles, slowness, or less protection than you wish you had.

Spyware blaster is not normally resident. Perhaps if you pay, its automatic update delivery might be running. The beauty of SB is that it does its job, and goes away. No conflicts possible.
Old but still valid reference
http://www.bleepingcomputer.com/tutorials/use-spywareblaster-to-protect-your-computer/